VBA: Read localstorage variable from Internet Explorer Object using temporary textfield

Here is a toy solution to access localstorage variables if they are not accessible directly.

Imagine we have test HTML webpage with HTML:

// Put the object into storage
localStorage.setItem('testObject', 'testString');

// Retrieve the object from storage
var retrievedObject = localStorage.getItem('testObject');

We can use the following VBA code to access the localstorage variable.

The code below executes javascript code that creates a temporary text field with the localstorage value. Following we are able to access the string value with getElementById and getAttributeValue.

Function retrieveLocalStorageValue(sURL As String, sLocalStorageVarName As String) As String

     On Error GoTo ErrHandler1:
        Dim javascriptString As String
        Set oBrowser = New InternetExplorer
        oBrowser.Silent = True
        oBrowser.navigate sURL
        oBrowser.Visible = True
        ' Wait till the Browser is loaded
        Loop Until oBrowser.readyState = READYSTATE_COMPLETE
    On Error GoTo ErrHandlerJscript:
        javastringUrl = "document.body.innerHTML += '<input id=\""test1234\"" type=\""text\"" value=\""'+ localStorage.getItem('" & sLocalStorageVarName & "') +'\""\>';"
        'Execute javascript to create hidden field - Use double quotes in VBA to escape
        'Wait in case it is needed
        Application.Wait DateAdd("s", 1, Now)
        oBrowser.document.parentWindow.eval javastringUrl
        retrieveLocalStorageValue = oBrowser.document.getElementById("test1234").getAttribute("value")
    Exit Function
    MsgBox ("Error, debugging required")
    retrieveLocalStorageValue = "error"
    MsgBox ("Error with javascript execution, debugging required")
    retrieveLocalStorageValue = "error"
End Function

Sub test()
    Dim test As String
    test = retrieveLocalStorageValue("", "testObject")
    MsgBox test
End Sub


Menelaos Bakopoulos

Mr. Menelaos Bakopoulos is currently pursuing his PhD both at Center for TeleInFrastruktur (CTiF) at Aalborg University (AAU) in Denmark and Athens Information Technology (AIT) in Athens, Greece. He received a Master in Information Technology and Telecommunications Systems from Athens Information Technology and a B.Sc. in Computer Science & Management Information Systems from the American College of Thessaloniki. Since April 2008 he has been a member of the Multimedia, Knowledge, and Web Technologies Group.

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